tdiv_qr.c
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上传日期:2022-08-06
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- /* mpz_tdiv_qr(quot,rem,dividend,divisor) -- Set QUOT to DIVIDEND/DIVISOR,
- and REM to DIVIDEND mod DIVISOR.
- Copyright 1991, 1993, 1994, 2000, 2001, 2005 Free Software Foundation, Inc.
- This file is part of the GNU MP Library.
- The GNU MP Library is free software; you can redistribute it and/or modify
- it under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 3 of the License, or (at your
- option) any later version.
- The GNU MP Library is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
- License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
- #include "gmp.h"
- #include "gmp-impl.h"
- #include "longlong.h"
- #ifdef BERKELEY_MP
- #include "mp.h"
- #endif
- void
- #ifndef BERKELEY_MP
- mpz_tdiv_qr (mpz_ptr quot, mpz_ptr rem, mpz_srcptr num, mpz_srcptr den)
- #else /* BERKELEY_MP */
- mdiv (mpz_srcptr num, mpz_srcptr den, mpz_ptr quot, mpz_ptr rem)
- #endif /* BERKELEY_MP */
- {
- mp_size_t ql;
- mp_size_t ns, ds, nl, dl;
- mp_ptr np, dp, qp, rp;
- TMP_DECL;
- ns = SIZ (num);
- ds = SIZ (den);
- nl = ABS (ns);
- dl = ABS (ds);
- ql = nl - dl + 1;
- if (dl == 0)
- DIVIDE_BY_ZERO;
- MPZ_REALLOC (rem, dl);
- if (ql <= 0)
- {
- if (num != rem)
- {
- mp_ptr np, rp;
- np = PTR (num);
- rp = PTR (rem);
- MPN_COPY (rp, np, nl);
- SIZ (rem) = SIZ (num);
- }
- /* This needs to follow the assignment to rem, in case the
- numerator and quotient are the same. */
- SIZ (quot) = 0;
- return;
- }
- MPZ_REALLOC (quot, ql);
- TMP_MARK;
- qp = PTR (quot);
- rp = PTR (rem);
- np = PTR (num);
- dp = PTR (den);
- /* FIXME: We should think about how to handle the temporary allocation.
- Perhaps mpn_tdiv_qr should handle it, since it anyway often needs to
- allocate temp space. */
- /* Copy denominator to temporary space if it overlaps with the quotient
- or remainder. */
- if (dp == rp || dp == qp)
- {
- mp_ptr tp;
- tp = TMP_ALLOC_LIMBS (dl);
- MPN_COPY (tp, dp, dl);
- dp = tp;
- }
- /* Copy numerator to temporary space if it overlaps with the quotient or
- remainder. */
- if (np == rp || np == qp)
- {
- mp_ptr tp;
- tp = TMP_ALLOC_LIMBS (nl);
- MPN_COPY (tp, np, nl);
- np = tp;
- }
- mpn_tdiv_qr (qp, rp, 0L, np, nl, dp, dl);
- ql -= qp[ql - 1] == 0;
- MPN_NORMALIZE (rp, dl);
- SIZ (quot) = (ns ^ ds) >= 0 ? ql : -ql;
- SIZ (rem) = ns >= 0 ? dl : -dl;
- TMP_FREE;
- }